Well…Time and Irvine are not very good friends…
The truth, I don’t think your path proposal, defining a new global SD, is the good answer.
To my mind, create a specific data type with certain characteristics, similar to the DNS type or Safecoin type could be better.
Might work as follows:
We define a new type of structured data (TimeStamp). Among its features we defined that can’t be erased and must contain:
.-Data owner (not always required)
To add a new record of TimeStamp type, a node sends a message to their managers with a time and interval. Managers send that data to all nodes in a group. Those who agree, answer affirmative.
When there are sufficient affirmative answers, we can use a accumulator, the new record, signed by the managers, is created. To be sure, we can demand that the new record is signed by two, three or even four managers.
If there are not enough affirmative answers, the request is considered erroneous and informs the node.
The node will use the Hash of this new record as TimeStamp. We can create a variable:
TimeStamp : i64
This data could be stored as evidence in any other data: other SD, in chunks of data, safecoin transfers, etc, etc,…